Liquid crystal display (LCD) devices are widely used for flat panel displays of images. As is well known to those having skill in the art, an LCD device generally includes a thin film transistor panel and a color filter panel which are spaced apart from one another. The thin film transistor panel generally includes a first substrate and a plurality of thin film transistors which are formed on the surface thereof. The color filter panel generally includes a second substrate and a color filter layer formed on a surface thereof. As is well known to those having skill in the art, it is generally desirable for LCD devices to have a high aperture ratio, to thereby improve the resolution thereof. The aperture ratio is the area through which a light beam is transmitted through the panel.
FIG. 1 is a cross-sectional view of a conventional color filter for an LCD device. As shown in FIG. 1, color filter 5 includes a light shielding layer 2 on a transparent substrate 1, such as glass. The light shielding layer includes an array of apertures therein. The light shielding layer 2 forms a black matrix for the color filter.
A color filter layer including red, green and blue color filters 3-1, 3-2 and 3-3 respectively, is formed on the light shielding layer 2 and spans the apertures therein. The color filters may be formed by depositing color dyes on the light shielding layer 2. Each color filter 3-1, 3-2 and 3-3 is formed between two adjacent light shielding portions and on the ends of the two adjacent light shielding portions. A protective layer 4 is formed on the light shielding layer 2 and the color filter layer.
A color filter according to FIG. 1 may be fabricated by forming an opaque layer, such as chromium, chromium oxide or organic material on a glass substrate 1 and then pattern in the opaque layer to form the light shielding layer 2. Color dyes of red, green and blue are then sequentially deposited and patterned to form the color filters 3-1, 3-2 and 3-3 respectively. Finally, a protective layer 4 is deposited over the color filters and the light shielding layer, to protect the color filter layer and to provide a smooth outer surface for the color filter.
In a conventional LCD device as described above, the aperture ratio is generally dependent upon the area through which a light beam from a back light on the thin film transistor panel is transmitted. In order to improve the resolution of the display, higher aperture ratios are generally desirable.
However, as shown in FIG. 1, a light beam 6 which is transmitted from the back light on the thin film transistor panel, will only penetrate the portion A of the color filter layer, but will not penetrate the portion A', due to the light shielding layer 2. Accordingly, the aperture ratio in a conventional LCD device may be reduced and it may become difficult to increase the resolution thereof.
In order to increase the aperture ratio, it may be desirable to form larger apertures in the light shielding layer 2. However, if the apertures in the light shielding layer are enlarged, it may be difficult to align the color filters 3-1, 3-2 and 3-3 to the apertures in the light shielding layer 2. Moreover, planarity problems may be produced.